via

viapreposition

American /ˈvaɪ.ə/ British /ˈvaɪ.ə/ also /ˈvi.ə/ also common: VEE-uh Most often said VY-uh; VEE-uh is also common.
  1. through a placethrough or stopping at a place on the way to somewhere else

    Compare through (via names a place passed on the way to somewhere else; through is about going into something and out of the other side)

  2. usingby using a person, system, or machine to send or do something

    Synonyms through

    Compare by (by is more usual with a way of sending in everyday speech: by email, by phone)

Usage

Via is common in writing and at work. In everyday speech, by is more usual for a way of sending (by email), and through for a person who passes something on (through a friend).